OLYMPIA, Wash. (AP) — A conservative Democrat who once opposed gay marriage now says he will support it.

Sen. Jim Kastama of Puyallup announced his decision Thursday, becoming the 24th senator to commit his vote to the measure. The chamber now needs to just one more yes vote from a group of a half-dozen uncommitted votes that remain.

The state House is widely expected to have enough support to pass gay marriage, and Gov. Chris Gregoire publicly endorsed the proposal earlier this month.

Kastama voted in 1998 for a law defining marriage as between one man and one woman. In 2009, he supported an expansion of the state’s domestic partnership laws.

He says society has changed and that it is necessary for marriage to evolve to strengthen marriage as a valued institution.

— Copyright 2012 The Associated Press